THAT MY LOVE is one of the hardest thing with expressions TTW TT This is something I can’t answer properly even though I already don’t give tutorials asdfgh 

On drawing we can’t always know if the perspective is right because it’s the same ol’ 3d turned into 2d TTW TT the way I got this also the same ol’ practice and observation, eventually, you’ll have this ability to understand how is it proportional at the same time lively ;;;w;;;; the most effective, for me at least, is doing the expressions yerself and look in the mirror.